This invention relates to heat exchangers, and more particularly, to an assembly of two heat exchangers which is such that assembly of the heat exchangers to each other or the disassembly of the two connected heat exchangers is easily effected.
Many applications involving heat exchangers require the assembly of two or more heat exchangers together such that a common heat exchange fluid passes through both heat exchangers serially. A common example is the heat exchanger system of a vehicle. In such systems, the heat exchange fluid common to plural heat exchangers that is customarily employed is air and heat exchanger components of many systems are located in the forward part of the vehicle frame to receive air which is either drawn or propelled through the heat exchanger by a fan or passes through the heat exchanger as a result of ram air effects. Not untypically, the heat exchangers may include radiators for cooling engine coolant, charge air coolers for cooling combustion compressed by a turbocharger or a super charger prior to being directed to the engine, condensers for air conditioning systems, etc.
These heat exchangers are assembled together in close proximity when installed in the vehicle because of space constraints in the engine compartment in which the heat exchangers are normally disposed. Further, the heat exchangers are located in close proximity to one another so as to allow for a minimal frontal area that in turn allows the designer of a vehicle to achieve a more aerodynamically slippery effect to promote fuel economy.
While these practices most certainly are beneficial, they are not without one undesirable side effect. Specifically, when one of the heat exchangers requires servicing, as for example, in repairing a leak or when the heat exchanger requires complete replacement, it is often difficult to achieve easy access to the affected heat exchanger to cause its removal for replacement or repair.
In an attempt to avoid this problem, German patent document 19857508A1 discloses a construction wherein lower struts of one heat exchanger are inserted into lower supports on another heat exchanger. The first heat exchanger is then pressed such that upper struts thereon snap into upper spring clasps. The spring clasp is a specially produced part, and thus expensive. It is mounted with a leg on a sleeve formed on the tank of the second heat exchanger such that the other leg exerts a vertical force on the upper and lower struts of the first heat exchanger and on the core of the first heat exchanger. Unfortunately, the core of the first heat exchanger, which typically consists of relatively thin-walled flat tubes and corrugated fins is placed under compression. Over time, this may lead to failures at various joints.
Other proposals in which spring clips are used as fastening elements in heat exchangers include DE-OS-2018459, EP0046566B1, DE-AS2557967, DE3814007C1, DE19857512A1 and DE19857494A1. Various disadvantages attend the use of these structures as well with the consequence that there remains a real need for a heat exchanger assembly held together by spring clips to permit ease of assembly and disassembly without the disadvantages of the prior art constructions. In particular, there remains a need for such an assembly wherein compressive forces on the core of one of the heat exchangers can be avoided without having a significant adverse affect on the desired goal to effect simple assembly and disassembly of the heat exchanger construction.
It is the principal object of the invention to provide a new and improved assembly of two heat exchangers wherein the two may be held in assembled relation by a removable spring clip without exerting undesirable forces on either of the heat exchangers.
An exemplary embodiment of the invention achieves the foregoing object in an assembly that includes a first heat exchanger having a core through which a coolant may pass and elongated, generally vertical, spaced tanks in fluid communication with the core. A second heat exchanger is provided with a core with elongated spaced tanks flanking the core. A support is disposed on each of the tanks of the first heat exchanger at a lower part thereof and a mount is disposed on each of the tanks of the first heat exchanger at an upper part thereof. Two spaced lower struts are located on the second heat exchanger and are received in respective ones of the supports. In addition, two spaced upper struts are located on the second heat exchanger aligned with respective ones of the mounts. A removable spring clip secures each of the upper struts to the mount with which it is aligned and imparts a torsional stress to the struts.
As a result of this construction, undesirable compressive or tensional stresses on one or the other of the heat exchangers is avoided while a tight assembly is maintained as a result of the torsional stress.
In a preferred embodiment, each of the upper mounts includes a pin directed toward the second heat exchanger and each upper strut includes a slot loosely receiving the pin on the associated upper mount. Each spring clip is a hairpin cotter key having one leg abutting the corresponding upper strut and another leg abutting the pin on the associated mount oppositely of the corresponding upper strut.
A preferred embodiment contemplates that the one leg of the hairpin cotter key is straight and the other leg includes a concave surface receiving the pin. The pin, at its point of abutment with the other leg of the hairpin cotter key has a convex surface received within the concave surface on the cotter key.
A preferred embodiment contemplates that the supports be J-shaped having a short leg and a long leg opening upwardly. The long leg, at a location remote from the short leg, has a protrusion extending toward the short leg and engaging the associated lower strut.
Preferably, the tanks, the mounts, the struts and the supports are formed of aluminum.
A highly preferred embodiment contemplates that the struts are brazed to the second heat exchanger tanks and that the mounts and the supports are cast in the first heat exchanger tanks.
Other objects and advantages will become apparent from the following specification taken in connection with the accompanying drawings.